LIFE PROCESSES: NUTRITION

Life Processes

Q 1. Define life processes.

Ans All the vital properties which are life supporting and helps in sustenance of life are called life processes. In other words it can be defined as maintenance processes or activities needed to make an organism alive e.g.

Nutrition

Respiration

Transportation

Excretion

Q2. What is the most basic characteristic of a living thing?

Ans The most basic characteristic of all living things is the occurrence of all the molecular movement (metabolism)

Q3. Why viruses have a controversial status?

Or

“Viruses are considered to be at the border line of living and non living.”

Ans Viruses are not made up of cells and do not show any molecular movement outside the host cell. It is therefore very risky to call them living organism. Therefore it is better to keep them as our border line.

Q4. Why do we need molecular movements?

Ans Living organism have well organized structures. They have tissues, tissues have cells and cells have smaller components in them. Because of the effect of environment these organized structures are likely to keep breaking down over the time. So to remains alive living organisms need to keep maintaining and repairing their structures.

Q5. What is nutrition?

Ans The process of obtaining food or to transfer the source of energy from outside the body to inside the body is called the nutrition.

Q6. “Life on earth is based on carbon based molecule” Explain.

Ans Multicellular organisms are made up of cells which are made up of carbon based molecules (organic compound) e.g. carbohydrates, fats, vitamins etc. Thus life is possible on earth due to carbon based molecule.

Q7. What is the importance of oxidizing reducing reaction in a living cell?

Ans Oxidizing reducing reactions are the most common means to break down the molecules to release energy. Without these reactions energy production is not possible.

Q8. What is respiration?

Ans The process of acquiring oxygen from outside the body and use it in the process of breakdown of food sources for cellular needs is what we call respiration.

Q9. What is the need of transport system in the body of organism?

Ans In the body of Multicellular organism the organs for the intake of food and oxygen are specific but oxygen is required for all the body parts. Therefore there is a need of transport system in order to make availability of system in different parts of the bodies to carry out cellular activities.

Q10. What is the need of excretory system?

Ans During the different metabolic activities or biochemical reactions taking place in our body, some bi-products which are useless and harmful for our body, is also produced. In order to remove these metabolic wastes and to prevent them from damaging any of the organs of the body, there is a need of excretory system in our body.

Q11. Why only diffusion alone cannot meet the oxygen demand in Multicellular body?

Ans in the body of a Multicellular organism all cells are not in direct contact with oxygen. Many cells are deeper placed and are away from the organs of intake. So they do not have the access to oxygen and will take very long to take in oxygen

NUTRITION

Q12. What is Nutrition?

Ans The process of intake of food, its digestion, absorption and distribution to different parts on the body is called nutrition. The term is derived from the word nutrients.

OR

The process of acquiring food material and changing it into simple absorbable forms with the help of bio chemical forms.

OR

It is the process by which organisms obtain energy in the form of food for their growth, repair, maintenance and reproduction etc.

Q13. Why different organisms have different mode of nutrition?

Ans The different organisms have different mode of nutrition due to their physiology and habitat etc.

Q14. What are bio-catalysts?

Ans Bio –catalysts are also called enzymes are basically organic substances prepared by living cells to regulate metabolic reactions.

When plant synthesis their food from simple inorganic raw materials or animals break food eaten by them into smaller units- all these processes are mediated by bio-catalysts.

AUTOTROPHIC NUTRITION

(Auto-self; tropism-nutrition)

{Examples- plants, and Bacteria}

The nutrition in which organisms can make all sources of energy from simple inorganic raw material.

Majority of autotrophs use light for the synthesis of organic food.  Since all green plant produce their food from this method called photosynthesis. They are called producers.

PHOTOSYNTHESIS (Plant Nutrition)

It is the process through which plants produces glucose and oxygen by carbon dioxide and hydrogen in the presence of sunlight and chlorophyll (a green pigment in the chloroplast of mesophyll cell.

6CO2 + 10H2O – C6H12O6 + 6O2 + 6H2O

Site of Photosynthesis

Plants –Leaves –Mesophyll cell- Chloroplast- Grana and Stroma

Photosynthesis:-

·       Light reaction

·       Dark reaction

Light Reaction

During light reaction following are the steps:-

a)   Absorption of light energy by chlorophyll and carotenoids (complex ,organic photo receptor molecules ) which are present in chloroplast

b)  Photolysis of water

c)   Generation of NADPH2 and ATP (reducing power)

Dark Reaction

Using the reducing power prepared during light phase, Co2 is progressively reduced to glucose (c6h12o6) in the stroma of chloroplasts

Q15. In which four plant and animal store food in the body?

Ans Plants store their food mainly in the form of sugar (starch) in their roots, modified stems, seeds, fruits etc.

Animals store their carbohydrate reserves mainly in the form of glycogen, in their liver and muscles.

Opening and closing of stomata

Stomata- They are tiny breathing pores that helps in gaseous exchange and transpiration. (Singular- Stoma)

(Stoma-guard cells + Stomatal opening)

Opening and closing of stoma occurs due to entry and exit of water in the guard cells. When the guard cells swells or become turgid due to the entry of water. The stomata are opened but when the guard cells shrink or become flaccid due to loss of water the stomata get closed.

Q16. How desert plant carries out photosynthesis as their stomata remains closed during the day time?

Ans Desert plants like cactus keep their stomata closed at day time to check the loss of water through transpiration and keep the stomata open at night to take in CO2 from the air. However they do not use CO2 at night rather convert it into so intermediate compound which is used for photosynthesis.

Q17.Why plants need nitrogen and how plants obtain it?

Ans Plants need nitrogen to synthesis various kinds of enzymes (proteins) Chlorophyll, ATP, Nucleic acids etc. Plants obtain nitrogen mainly from the soil in the form of nitrides and Ammonium ions.

Q18.Mention the role of bacteria in plant nutrition.

Ans Some symbiotic and free bacteria can ix atmospheric nitrogen to some usable form which can be absorbed and utilized by plants.

Some can solublize like Ca, P, etc from the rock and make them available for plants.

Nutrition

a)   Autotrophic- 1. Phototrophic (utilizes solar energy)

                                2. Chemotropic(utilizes chemical energy)

b)  Heterotrophic- 1. Holozoic

                           2. Saprophytic

                           3. Parasitic

                           4. Symbiotic

c)   Mixotrophic (partly autotrophic and heterotrophic)

Autotrophic Nutrition

In this mode of nutrition , living organism manufacture their food by converting inorganic substance to organic by the process of photosynthesis and Chemosynthesis. The organisms doing so are called autotrophs or self feeder or producers e.g. plant, bacteria, cyanobacteria (blue green algae).

Q19. What are the raw materials required for photosynthesis?

Ans The raw materials required for photosynthesis are:-

                              i.            Sunlight

                          ii.            Chlorophyll

                       iii.            Carbon dioxide

                        iv.            Water

Heterotrophic Nutrition

In this mode of nutrition organisms obtain their food by some other organisms either in the form of living or dead, plants or animals. In this mode of nutrition the complex organic food is taken inside the body through any of the modes and are broken down with the help of digestion e.g. animals humans etc.

Mixotrophic

In this type of nutrition partially the food is prepared and partly obtained. e.g. lichens.

Q20. What are the different types of heterotrophic nutrition?

Ans Holozoic- (holo- complete/whole +zoom)

In this type of nutrition all types of animals including humans obtain their nutrition by ingesting he whole food through mouth or similar structure by ingestion the ingested matter is subsequently, digested, absorbed by the body and finally egested out of the body.

Depending upon the type of their habitat Holozoic are of 3 types:-

                           i.            Herbivores (deer, goat etc)

                       ii.            Carnivores (lion, tiger, etc)

                    iii.            Omnivores (humans, cats, dogs, etc)

Saprophytic- In this mode of nutrition the organisms feed on dead and decaying matter(plants and animals parts). They are also called ‘saprophytes’. In this nutrition the complex organic matter is first dissolved by secreting some “hydrolyzing enzyme” and then the soluble matter is absorbed through the body surface.

Parasitic-In this mode of nutrition the organisms derives its nutrition or food from other living organisms. It involves two types of organisms .

                           i.            Who derives the nutrition from other organisms is called parasite.

                       ii.            And the one from whom the food is derived is called the host. The host can be a plant or animal.

A parasite lives either inside (endo parasite) or on the body (ecto parasite) of the host.